Magnesium and aluminum alloys are widely used in various industries because of their excellent properties,and their reliable connection may increase application of materials.Intermetallic compounds(IMCs)affect the joi...Magnesium and aluminum alloys are widely used in various industries because of their excellent properties,and their reliable connection may increase application of materials.Intermetallic compounds(IMCs)affect the joint performance of Mg/Al.In this study,AZ31 Mg alloy with/without a nickel(Ni)coating layer and 6061 Al alloy were joined by ultrasonic-assisted soldering with Sn-3.0Ag-0.5Cu(SAC)filler.The effects of the Ni coating layer on the microstructure and mechanical properties of Mg/Al joints were systematically investigated.The Ni coating layer had a significant effect on formation of the Mg_(2)Sn IMC and the mechanical properties of Mg/Al joints.The blocky Mg_(2)Sn IMC formed in the Mg/SAC/Al joints without a Ni coating layer.The content of the Mg_(2)Sn IMC increased with increasing soldering temperature,but the joint strength decreased.The joint without a Ni coating layer fractured at the blocky Mg_(2)Sn IMC in the solder,and the maximum shear strength was 32.2 MPa.By pre-plating Ni on the Mg substrate,formation of the blocky Mg_(2)Sn IMC was inhibited in the soldering temperature range 240–280℃and the joint strength increased.However,when the soldering temperature increased to 310℃,the blocky Mg_(2)Sn IMC precipitated again in the solder.Transmission electron microscopy showed that some nano-sized Mg_(2)Sn IMC and the(Cu,Ni)_(6)Sn_(5)phase formed in the Mg(Ni)/SAC/Al joint soldered at 280℃,indicating that the Ni coating layer could no longer prevent diffusion of Mg into the solder when the soldering temperature was higher than 280℃.The maximum shear strength of the Mg(Ni)/SAC/Al joint was 58.2 MPa for a soldering temperature of 280℃,which was 80.7%higher than that of the Mg/SAC/Al joint,and the joint was broken at the Mg(Ni)/SAC interface.Pre-plating Ni is a feasible way to inhibit formation of IMCs when joining dissimilar metals.展开更多
Immersion experiment results show that corrosion rate of the as deposited RE Ni W P SiC composite coating in HCl solutions increases with the rise of HCl concentration. On the contrary, the corrosion rate of the compo...Immersion experiment results show that corrosion rate of the as deposited RE Ni W P SiC composite coating in HCl solutions increases with the rise of HCl concentration. On the contrary, the corrosion rate of the composite coating after heat treatment decreases with increasing HCl concentration. The corrosion rates of the composite coatings in as deposited state and after heat treatment in H 2SO 4 and H 3PO 4 solutions respectively decrease with the rise of H 2SO 4 and H 3PO 4 concentrations. The corrosion rate of the composite coating as deposited in FeCl 3 solutions decreases with increasing FeCl 3 concentration, while the rate of the composite coating after heat treatment increases with the rise of FeCl 3 concentration. The corrosion rate of 316L stainless steel in the corrosion media of H 2SO 4, HCl, H 3PO 4 and FeCl 3 solutions at different concentrations increases with rising concentration. In addition, the corrosion rate of 316L stainless steel in the corrosion media of H 2SO 4, HCl, H 3PO 4 and FeCl 3 solutions respectively is much greater than that of the RE Ni W P SiC composite coating as deposited and after heat treatment in the same corrosion media. [展开更多
The effects of rare earth (RE) on the composition, phase structures, surface morphologies and hardness of electrodeposited RE Ni W B SiC composite coatings were discussed. The results show that W and SiC contents in t...The effects of rare earth (RE) on the composition, phase structures, surface morphologies and hardness of electrodeposited RE Ni W B SiC composite coatings were discussed. The results show that W and SiC contents in the coatings increase with the increase of RE in the bath. When RE is added in the coatings, the grains are refined and the trend of formation of amorphous coatings is increased. Moreover, the thermal stability of the RE Ni W B SiC composite coatings is enhanced. The hardness of the coatings is increased with the increase of heat treatment temperature, and it reaches the peak value when heated at 400 ℃. Besides, the hardness of the RE Ni W B SiC coatings is higher than that of the Ni W B SiC coatings.展开更多
The components and microstructure of the RE Ni W P SiC composite coating were analyzed by means of EPXDS, SEM and XRD. The results showed that the composite coating containing 5%~14%RE, 4%~7%SiC, 12%~15%P and 5%~6...The components and microstructure of the RE Ni W P SiC composite coating were analyzed by means of EPXDS, SEM and XRD. The results showed that the composite coating containing 5%~14%RE, 4%~7%SiC, 12%~15%P and 5%~6%W was obtained by use of appropriate bath composition and plating conditions. The as deposited composite coating is amorphous and it becomes mixture when the temperature is raised from 200 ℃ to 400 ℃. However, the composite coating is crystal when the temperature is over 400 ℃. Scanning electron microscopy indicates that the heat treatment temperature has no effect on the surface morphologies of the RE Ni W P SiC composite coating. This is to say that the composite coating has a better heat stability of microstructure and high temperature oxidation.展开更多
To improve the low thermal conductivities and poor wear resistances of TC4(Ti-6Al-4V)alloy,the most widely used titanium alloy,the surface of TC4 alloys is modified by electroplating deposition of Ni and Cu layers,and...To improve the low thermal conductivities and poor wear resistances of TC4(Ti-6Al-4V)alloy,the most widely used titanium alloy,the surface of TC4 alloys is modified by electroplating deposition of Ni and Cu layers,and then heat-treated to increase the diffusivity at the interface.In this paper,the corrosion behavior of Cu/Ni coatings on TC4 alloy at different heat treatment processes was investigated in 3.5 wt%Na Cl by the electrochemical analysis,and the microstructure and composition of corrosion products was carried out to reveal the corrosion resistance mechanism of Cu/Ni coatings.It was found that the corrosion resistance was significantly influenced by heat treatment temperature.With the increasing diffusion treatment temperature from 500 to 700℃,the corrosion potential positively shifted from-330.87 to-201.14 m V,and the corrosion current density decreased from 4.02×10^-3 to 0.514×10^-3 m A/cm^2.However,when heat treatment temperature increased to 800℃,the corrosion potential negatively shifted to-207.21 m V,and the current density increased to 1.62×10^-3 m A/cm^2.The diffusion behavior of Ti,Ni and Cu elements occurred and small amounts of Ni and Ti elements appeared on the specimen surface under different heat treatment temperature.Especially heattreated at 700℃,the smaller pore size,dense Cu2O film,and highly stable Ti O and Ni O oxide layer were formed,which dramatically enhanced the corrosion resistance of Cu/Ni coatings.Finally,a novel model of corrosion resistance was proposed based on the analysis mentioned above.展开更多
The φ pH diagram of Ni B H 2O system was drawn, and the mechanism of electrodepositing Ni B SiC composite coatings was discussed. The results show that the deposition of Ni and B occurs prior to that of H 2 because o...The φ pH diagram of Ni B H 2O system was drawn, and the mechanism of electrodepositing Ni B SiC composite coatings was discussed. The results show that the deposition of Ni and B occurs prior to that of H 2 because of the over potential of H 2 evolution on the Fe substrate. Boron can not singly deposit in aqueous solution. Nickel and boron can co deposit in the form of Ni 4B 3 without evolution of hydrogen when the cathodical potential is kept to be -1.415 ~ -1.700?V.展开更多
The thermal barrier coatings with NiCrAlY alloy bonding layer, NiCrAlY Y 2O 3 stabilized ZrO 2 transition layer and Y 2O 3 stabilized ZrO 2 ceramic layer are prepared on nickel alloy substrates using the plasma spray ...The thermal barrier coatings with NiCrAlY alloy bonding layer, NiCrAlY Y 2O 3 stabilized ZrO 2 transition layer and Y 2O 3 stabilized ZrO 2 ceramic layer are prepared on nickel alloy substrates using the plasma spray technique. The relationship among the composition, structure and property of the coatings are investiga ted by means of optical microscope, scanning electronic microscope and the experiments of thermal shock resistance cycling and high temperature oxidation resistance. The results show that the structure design of introdu cing a transition layer between Ni alloy substrate and ZrO 2 ceramic coating guarantees the high quality and properties of the coatings; ZrO 2 coatings doped with a little SiO 2 possesses better thermal shock resistance and more excellent hot corrosion resistance as compared with ZrO 2 coating materials without SiO 2 ;the improvement in performance of ZrO 2 coating doped with SiO 2 is due to forming more dense coating structure by self closing effects of the flaws and pores in the ZrO 2 coatings.展开更多
The present paper aims to investigate the influence of the current density in the electroplating process on the microstructure, crystal texture transformations, and corrosion behavior of Ni/Co pumice multilayer nanoco...The present paper aims to investigate the influence of the current density in the electroplating process on the microstructure, crystal texture transformations, and corrosion behavior of Ni/Co pumice multilayer nanocomposite coatings. The Ni/Co pumice composite coatings were prepared by deposition of Ni, followed by the simultaneous deposition of pumice nanoparticles (NPs) in a Co matrix via an electroplating process at various current densities. Afterward, the morphology, size, topography, and crystal texture of the obtained samples were investigated. Furthermore, electrochemical methods were used to investigate the corrosion behavior of the produced coatings in a solution of 3.5wt% NaCl. The results indicated that increasing the plating current density changed the mechanism of coating growth from the cell state to the column state, in- creased the coating thickness, roughness, and texture coefficient (TC) of the Co (203) plane, and reduced the amount of pumice NPs incorporated into the Ni/Co pumice composite. The electrochemical results also indicated that increasing the current density enhanced the corrosion resistance of the Ni/Co pumice composite.展开更多
There is a great challenge to fabricate superhydrophobic coating with excellent mechanical durability and corrosion resistance.Inspired by the pinecone-shaped structure,a novel reduced-graphene oxide(rGO)/Ni composite...There is a great challenge to fabricate superhydrophobic coating with excellent mechanical durability and corrosion resistance.Inspired by the pinecone-shaped structure,a novel reduced-graphene oxide(rGO)/Ni composite coating with pinecone-like micro/nanostructures was fabricated successfully on a stainless steel substrate using a simple electrodeposition method combining Ni pre-deposition and an elevated current assistant approach.The results show that the coating is of self-cleaning and superhydrophicity with a water contact angle(CA)of 162.7°±0.8°and a sliding angle(SA)of 2.5°±1.0°.Importantly,the coating still maintains the excellent self-cleaning and superhydrophicity,water CA of 155.8°±1.2°and SA of 5.9°±1.2°,even after 100-cycle mechanical abrasion.Meanwhile,the coating also exhibits good anticorrosion performance in 3.5 wt%NaCl solution,with 99.98%inhibition efficiency.The simple fabrication method may provide a cost-effective way to prepare mechanically durable,anticorrosive,self-cleaning and superhydrophobic coatings on metal substrates.展开更多
By adding rare earth alloy and cerium oxide, the effect of rare earths on tribological properties of nickel base alloy layer was studied to approach the possibility of applying rare earths to Ni base thermal spray ...By adding rare earth alloy and cerium oxide, the effect of rare earths on tribological properties of nickel base alloy layer was studied to approach the possibility of applying rare earths to Ni base thermal spray welding coating. Wear test results showed that the wear rates of the nickel base coating without rare earths were quite high, and the load bearing capacity of coating was low, in contrast, the wear rates of the coating with rare earths were low and the coating had higher load bearing capacity. The results show that rare earths can refine the structure of nickel base alloy, improve the interface of the coating and substrate.展开更多
Two types of plasma sprayed coatings (NiCrAlY and NiCrAlY-A12O3) were remelted by a 5 kW cw CO2 laser. With increasing laser power and decreasing traverse speed in the ranges of 200-700 W and 5-30 mm/s respectively, t...Two types of plasma sprayed coatings (NiCrAlY and NiCrAlY-A12O3) were remelted by a 5 kW cw CO2 laser. With increasing laser power and decreasing traverse speed in the ranges of 200-700 W and 5-30 mm/s respectively, the melted track grew in width and depth. In the optimum range of laser parameters, a homogeneous remelted layer without voids, cavities, unmelted particles and microcracks was formed. On the surface of remelted layers, Al203 and YAIO3 were detected. As a result of isothermal oxidation tests, weight gains of laser remelted coatings were obviously lower than that only plasma sprayed, especially laser remelted NiCrAlY-Al2O3 coatings. The effects of laser remelting and incorporation of A12O3 second phase in N1CrAlY matrix on high temperature oxidation resistance were discussed.展开更多
Ni-based composite coatings incorporated with nano/micron SiC particles were fabricated via electrochemical co-deposition in Watts bath,followed by the evaluation of their mechanical and anti-corrosion properties.The ...Ni-based composite coatings incorporated with nano/micron SiC particles were fabricated via electrochemical co-deposition in Watts bath,followed by the evaluation of their mechanical and anti-corrosion properties.The micrographic observations suggest that the SiC particles with various sizes can be well incorporated to the Ni substrate.X-ray diffraction(XRD)patterns indicate that SiC particles with smaller sizes could weaken the preferential growth of Ni along(200)facet.In addition,it is found that the incorporated SiC particles with medium micron sizes(8 and 1.5μm)could significantly enhance the micro-hardness of the Ni composite coatings.Nevertheless,electrochemical measurements demonstrate that micron-sized SiC particles would weaken the corrosion resistance of Ni composite coatings ascribed to the structure defects induced.In contrast,the combined incorporation of nanosized(50 nm)SiC particles with medium micron(1.5μm)ones is capable of promoting the compactness of the composite coatings,which is beneficial to the long-term corrosion resistance with negligible micro-hardness loss.展开更多
A series of single bcc,bcc plus fcc duplex and single fcc microcrystalline coatings of 1Cr18Ni9Ti stainless steel were prepared by using sputtering technique.The resistance against pitting corrosion was studied by mea...A series of single bcc,bcc plus fcc duplex and single fcc microcrystalline coatings of 1Cr18Ni9Ti stainless steel were prepared by using sputtering technique.The resistance against pitting corrosion was studied by measurements of pitting corrosion potentials and electrochemical noise during initiation of corrosion pits.The results show that the sputtered coatings with single bcc phase or single fcc structure are more resistant to pitting corrosion than those with bcc plus fcc duplex phase structure.展开更多
基金financial support from the National Natural Science Foundation of China(grant numbers 52275385 and U2167216)the Sichuan Province Science and Technology Support Program(grant number 2022YFG0086)。
文摘Magnesium and aluminum alloys are widely used in various industries because of their excellent properties,and their reliable connection may increase application of materials.Intermetallic compounds(IMCs)affect the joint performance of Mg/Al.In this study,AZ31 Mg alloy with/without a nickel(Ni)coating layer and 6061 Al alloy were joined by ultrasonic-assisted soldering with Sn-3.0Ag-0.5Cu(SAC)filler.The effects of the Ni coating layer on the microstructure and mechanical properties of Mg/Al joints were systematically investigated.The Ni coating layer had a significant effect on formation of the Mg_(2)Sn IMC and the mechanical properties of Mg/Al joints.The blocky Mg_(2)Sn IMC formed in the Mg/SAC/Al joints without a Ni coating layer.The content of the Mg_(2)Sn IMC increased with increasing soldering temperature,but the joint strength decreased.The joint without a Ni coating layer fractured at the blocky Mg_(2)Sn IMC in the solder,and the maximum shear strength was 32.2 MPa.By pre-plating Ni on the Mg substrate,formation of the blocky Mg_(2)Sn IMC was inhibited in the soldering temperature range 240–280℃and the joint strength increased.However,when the soldering temperature increased to 310℃,the blocky Mg_(2)Sn IMC precipitated again in the solder.Transmission electron microscopy showed that some nano-sized Mg_(2)Sn IMC and the(Cu,Ni)_(6)Sn_(5)phase formed in the Mg(Ni)/SAC/Al joint soldered at 280℃,indicating that the Ni coating layer could no longer prevent diffusion of Mg into the solder when the soldering temperature was higher than 280℃.The maximum shear strength of the Mg(Ni)/SAC/Al joint was 58.2 MPa for a soldering temperature of 280℃,which was 80.7%higher than that of the Mg/SAC/Al joint,and the joint was broken at the Mg(Ni)/SAC interface.Pre-plating Ni is a feasible way to inhibit formation of IMCs when joining dissimilar metals.
文摘Immersion experiment results show that corrosion rate of the as deposited RE Ni W P SiC composite coating in HCl solutions increases with the rise of HCl concentration. On the contrary, the corrosion rate of the composite coating after heat treatment decreases with increasing HCl concentration. The corrosion rates of the composite coatings in as deposited state and after heat treatment in H 2SO 4 and H 3PO 4 solutions respectively decrease with the rise of H 2SO 4 and H 3PO 4 concentrations. The corrosion rate of the composite coating as deposited in FeCl 3 solutions decreases with increasing FeCl 3 concentration, while the rate of the composite coating after heat treatment increases with the rise of FeCl 3 concentration. The corrosion rate of 316L stainless steel in the corrosion media of H 2SO 4, HCl, H 3PO 4 and FeCl 3 solutions at different concentrations increases with rising concentration. In addition, the corrosion rate of 316L stainless steel in the corrosion media of H 2SO 4, HCl, H 3PO 4 and FeCl 3 solutions respectively is much greater than that of the RE Ni W P SiC composite coating as deposited and after heat treatment in the same corrosion media. [
文摘The effects of rare earth (RE) on the composition, phase structures, surface morphologies and hardness of electrodeposited RE Ni W B SiC composite coatings were discussed. The results show that W and SiC contents in the coatings increase with the increase of RE in the bath. When RE is added in the coatings, the grains are refined and the trend of formation of amorphous coatings is increased. Moreover, the thermal stability of the RE Ni W B SiC composite coatings is enhanced. The hardness of the coatings is increased with the increase of heat treatment temperature, and it reaches the peak value when heated at 400 ℃. Besides, the hardness of the RE Ni W B SiC coatings is higher than that of the Ni W B SiC coatings.
文摘The components and microstructure of the RE Ni W P SiC composite coating were analyzed by means of EPXDS, SEM and XRD. The results showed that the composite coating containing 5%~14%RE, 4%~7%SiC, 12%~15%P and 5%~6%W was obtained by use of appropriate bath composition and plating conditions. The as deposited composite coating is amorphous and it becomes mixture when the temperature is raised from 200 ℃ to 400 ℃. However, the composite coating is crystal when the temperature is over 400 ℃. Scanning electron microscopy indicates that the heat treatment temperature has no effect on the surface morphologies of the RE Ni W P SiC composite coating. This is to say that the composite coating has a better heat stability of microstructure and high temperature oxidation.
基金Funded by Key Projects of Shaanxi Natural Science Foundation(No.2019JZ-27)Shaanxi Natural Science Basic Research Program-Shaanxi Coal(No.2019JLM-47)Fundamental Research Funds for the Central Universities CHD(No.300102319304).
文摘To improve the low thermal conductivities and poor wear resistances of TC4(Ti-6Al-4V)alloy,the most widely used titanium alloy,the surface of TC4 alloys is modified by electroplating deposition of Ni and Cu layers,and then heat-treated to increase the diffusivity at the interface.In this paper,the corrosion behavior of Cu/Ni coatings on TC4 alloy at different heat treatment processes was investigated in 3.5 wt%Na Cl by the electrochemical analysis,and the microstructure and composition of corrosion products was carried out to reveal the corrosion resistance mechanism of Cu/Ni coatings.It was found that the corrosion resistance was significantly influenced by heat treatment temperature.With the increasing diffusion treatment temperature from 500 to 700℃,the corrosion potential positively shifted from-330.87 to-201.14 m V,and the corrosion current density decreased from 4.02×10^-3 to 0.514×10^-3 m A/cm^2.However,when heat treatment temperature increased to 800℃,the corrosion potential negatively shifted to-207.21 m V,and the current density increased to 1.62×10^-3 m A/cm^2.The diffusion behavior of Ti,Ni and Cu elements occurred and small amounts of Ni and Ti elements appeared on the specimen surface under different heat treatment temperature.Especially heattreated at 700℃,the smaller pore size,dense Cu2O film,and highly stable Ti O and Ni O oxide layer were formed,which dramatically enhanced the corrosion resistance of Cu/Ni coatings.Finally,a novel model of corrosion resistance was proposed based on the analysis mentioned above.
文摘The φ pH diagram of Ni B H 2O system was drawn, and the mechanism of electrodepositing Ni B SiC composite coatings was discussed. The results show that the deposition of Ni and B occurs prior to that of H 2 because of the over potential of H 2 evolution on the Fe substrate. Boron can not singly deposit in aqueous solution. Nickel and boron can co deposit in the form of Ni 4B 3 without evolution of hydrogen when the cathodical potential is kept to be -1.415 ~ -1.700?V.
文摘The thermal barrier coatings with NiCrAlY alloy bonding layer, NiCrAlY Y 2O 3 stabilized ZrO 2 transition layer and Y 2O 3 stabilized ZrO 2 ceramic layer are prepared on nickel alloy substrates using the plasma spray technique. The relationship among the composition, structure and property of the coatings are investiga ted by means of optical microscope, scanning electronic microscope and the experiments of thermal shock resistance cycling and high temperature oxidation resistance. The results show that the structure design of introdu cing a transition layer between Ni alloy substrate and ZrO 2 ceramic coating guarantees the high quality and properties of the coatings; ZrO 2 coatings doped with a little SiO 2 possesses better thermal shock resistance and more excellent hot corrosion resistance as compared with ZrO 2 coating materials without SiO 2 ;the improvement in performance of ZrO 2 coating doped with SiO 2 is due to forming more dense coating structure by self closing effects of the flaws and pores in the ZrO 2 coatings.
文摘The present paper aims to investigate the influence of the current density in the electroplating process on the microstructure, crystal texture transformations, and corrosion behavior of Ni/Co pumice multilayer nanocomposite coatings. The Ni/Co pumice composite coatings were prepared by deposition of Ni, followed by the simultaneous deposition of pumice nanoparticles (NPs) in a Co matrix via an electroplating process at various current densities. Afterward, the morphology, size, topography, and crystal texture of the obtained samples were investigated. Furthermore, electrochemical methods were used to investigate the corrosion behavior of the produced coatings in a solution of 3.5wt% NaCl. The results indicated that increasing the plating current density changed the mechanism of coating growth from the cell state to the column state, in- creased the coating thickness, roughness, and texture coefficient (TC) of the Co (203) plane, and reduced the amount of pumice NPs incorporated into the Ni/Co pumice composite. The electrochemical results also indicated that increasing the current density enhanced the corrosion resistance of the Ni/Co pumice composite.
基金the National Natural Science Foundation of China(No.51671050)partially supported by the National Key R&D Program of China(No.2017YFB0305800)the Joint Founds of NSFC Liaoning(No.U1508213).
文摘There is a great challenge to fabricate superhydrophobic coating with excellent mechanical durability and corrosion resistance.Inspired by the pinecone-shaped structure,a novel reduced-graphene oxide(rGO)/Ni composite coating with pinecone-like micro/nanostructures was fabricated successfully on a stainless steel substrate using a simple electrodeposition method combining Ni pre-deposition and an elevated current assistant approach.The results show that the coating is of self-cleaning and superhydrophicity with a water contact angle(CA)of 162.7°±0.8°and a sliding angle(SA)of 2.5°±1.0°.Importantly,the coating still maintains the excellent self-cleaning and superhydrophicity,water CA of 155.8°±1.2°and SA of 5.9°±1.2°,even after 100-cycle mechanical abrasion.Meanwhile,the coating also exhibits good anticorrosion performance in 3.5 wt%NaCl solution,with 99.98%inhibition efficiency.The simple fabrication method may provide a cost-effective way to prepare mechanically durable,anticorrosive,self-cleaning and superhydrophobic coatings on metal substrates.
文摘By adding rare earth alloy and cerium oxide, the effect of rare earths on tribological properties of nickel base alloy layer was studied to approach the possibility of applying rare earths to Ni base thermal spray welding coating. Wear test results showed that the wear rates of the nickel base coating without rare earths were quite high, and the load bearing capacity of coating was low, in contrast, the wear rates of the coating with rare earths were low and the coating had higher load bearing capacity. The results show that rare earths can refine the structure of nickel base alloy, improve the interface of the coating and substrate.
文摘Two types of plasma sprayed coatings (NiCrAlY and NiCrAlY-A12O3) were remelted by a 5 kW cw CO2 laser. With increasing laser power and decreasing traverse speed in the ranges of 200-700 W and 5-30 mm/s respectively, the melted track grew in width and depth. In the optimum range of laser parameters, a homogeneous remelted layer without voids, cavities, unmelted particles and microcracks was formed. On the surface of remelted layers, Al203 and YAIO3 were detected. As a result of isothermal oxidation tests, weight gains of laser remelted coatings were obviously lower than that only plasma sprayed, especially laser remelted NiCrAlY-Al2O3 coatings. The effects of laser remelting and incorporation of A12O3 second phase in N1CrAlY matrix on high temperature oxidation resistance were discussed.
基金This work was financially supported by National Natural Science Foundation of China(Nos.51901018 and 51771027)National Science and Technology Resources In-vestigation Program of China(No.2019FY101400)+3 种基金Funda-mental Research Funds for the Central Universities,China(Nos.FRF-MP-19-001 and FRF-AT-20-07)National Key Research and Development Program of China(No.2017YFB0702100)China Postdoctoral Science Foundation(No.2019M660456)Young Elite Scientists Sponsor-ship Program by China Association for Science and Techno-logy(YESS,No.2019QNRC001).
文摘Ni-based composite coatings incorporated with nano/micron SiC particles were fabricated via electrochemical co-deposition in Watts bath,followed by the evaluation of their mechanical and anti-corrosion properties.The micrographic observations suggest that the SiC particles with various sizes can be well incorporated to the Ni substrate.X-ray diffraction(XRD)patterns indicate that SiC particles with smaller sizes could weaken the preferential growth of Ni along(200)facet.In addition,it is found that the incorporated SiC particles with medium micron sizes(8 and 1.5μm)could significantly enhance the micro-hardness of the Ni composite coatings.Nevertheless,electrochemical measurements demonstrate that micron-sized SiC particles would weaken the corrosion resistance of Ni composite coatings ascribed to the structure defects induced.In contrast,the combined incorporation of nanosized(50 nm)SiC particles with medium micron(1.5μm)ones is capable of promoting the compactness of the composite coatings,which is beneficial to the long-term corrosion resistance with negligible micro-hardness loss.
文摘A series of single bcc,bcc plus fcc duplex and single fcc microcrystalline coatings of 1Cr18Ni9Ti stainless steel were prepared by using sputtering technique.The resistance against pitting corrosion was studied by measurements of pitting corrosion potentials and electrochemical noise during initiation of corrosion pits.The results show that the sputtered coatings with single bcc phase or single fcc structure are more resistant to pitting corrosion than those with bcc plus fcc duplex phase structure.